Of all the stainless steel existing in the world today, perhaps the most unique of them is duplex (S31803 or 2205), a dual-phase stainless steel that’s about as versatile as they come. Used regularly in the oil and chemical processing industries, it’s renowned primarily for its corrosion resistance capabilities.
Interested in learning about the structure of duplex stainless steel? Then read on. This blog post has you covered. The Composition of Duplex Stainless Steel
In order to understand the composition of duplex stainless steel, you must first gain an understanding of austenitic and ferritic stainless steel. Why? Because duplex stainless steel consists of both austenitic and ferritic phases.
In fact, duplex is essentially half austenitic and half ferritic, meaning it shares characteristics of each. We’ll get into a little more information on austenitic and ferritic stainless steels below. Austenitic Stainless Steel
Non-magnetic in nature, austenitic stainless steels are characterized by high chromium content, high nickel content, and low carbon content. Easily formable and resistant to corrosion, they are the most commonly used stainless steels in the world.
Unfortunately, due to a large amount of nickel contained within them, austenitic stainless steels are expensive. This is one of the reasons that duplex stainless steel exists—to provide characteristics similar to austenitic steel at a fraction of its price. Ferritic Stainless Steel
Magnetic in nature, ferritic stainless steels are characterized by low chromium content, low nickel content, and high iron content. Capable of being hardened, and showing excellent strength against stress corrosion cracking, they work terrifically in corrosive, high-impact, environments.
Because it doesn’t contain much nickel, ferritic stainless steel is very affordable. This is part of the reason that it’s used to create duplex. In What Ways Does Duplex Stainless Steel Excel?
Duplex stainless steel has a number of positive characteristics and excels in a variety of ways. Some of the most prominent characteristics of duplex include the following. It’s Resistant to Corrosion
First and foremost, we need to mention duplex stainless steel’s resistance to corrosion. This class of steel is resistant to all types of corrosion, including pitting, crevice corrosion, stress-corrosion cracking, and more. Ideally suited for use in salt water, it’s very often utilized in the underwater oil industry. It’s Strong
In addition to providing top-notch corrosion resistance, duplex stainless steel also provides above-average strength capabilities. While it’s not the absolute strongest stainless steel on the market, it holds up remarkably well against physical trauma.
This is particularly true for the amount of corrosion resistance it provides. While there are stronger stainless steels available, they are much more susceptible to corrosion. It’s Weldable
Another characteristic that duplex stainless possesses is weldability. While it can’t be welded as easily as some other stainless steel, it at least possesses the capability.
One thing to note is that, if you’re going to weld with duplex, it’s important that you understand what you’re doing. Not only will you need to use the right filler metal, but you’ll have to use precise temperatures as well. It’s not the first choice for welding purposes, but it can suffice if needed. It’s Affordable
Duplex stainless steel is not the most affordable stainless steel on the market, but when you consider how versatile it is, it’s a great bargain. Few stainless steels can provide its collection of positive characteristics at its price point.